tests: fix printf format compiler warning in playback test on win32

https://bugzilla.gnome.org/show_bug.cgi?id=729515

tests/examples/playback/playback-test.c

@@ -2130,8 +2130,8 @@ realize_cb (GtkWidget * widget, PlaybackApp * app)
     g_error ("Couldn't create native window needed for GstVideoOverlay!");
 
 #if defined (GDK_WINDOWING_WIN32)
-  app->embed_xid = GDK_WINDOW_HWND (window);
-  g_print ("Window realize: video window HWND = %lu\n", app->embed_xid);
+  app->embed_xid = (guintptr) GDK_WINDOW_HWND (window);
+  g_print ("Window realize: video window HWND = %" G_GUINTPTR_FORMAT "\n", app->embed_xid);
 #elif defined (GDK_WINDOWING_QUARTZ)
   app->embed_xid = (guintptr) gdk_quartz_window_get_nsview (window);
   g_print ("Window realize: video window NSView = %p\n", app->embed_xid);